As usual, click any photo to bring up a larger version.
This is one project where I think you really need to see it in action in order to properly appreciate it fully. So please, watch the above youtube video first, and then come back and read the rest of this web page for more photos and more details.
I came up with this design as a way to re-invent the classic marble drop toy. By using a piece of plywood for the back you vastly simplify the construction.
I designed my toy to have two parallel tracks for the marbles to follow. This increases the noise, it increases visual interest, and most importantly of all, it allows your kids to have races.
Finally, I added a bell to my design. Again, this adds to the noise, and more noise is good in a marble toy! There is also the idea that each marble gets to ring the bell as it arrives at the "finish line" of the racetrack.
Marble track pieces can be nailed or glued very easily to the flat back. If you like, this is a great project to have your child help you build. You can have fun coming up with different marble track layouts.
What follows are a series of comments about various aspects of the racetrack construction, as well as many photos.
Rear view of the Marble Racetrack.
This is a sort of 2-dimensional project. All the tracks are attached to a piece of plywood.
I also recommend buying your bell before construction, as it's size will affect other dimensions. When I built my toy, I was able to buy a brass counter/desk bell kit at Lee Valley. It's no longer available there, but you can find desk bells (or counter bells) at office supply stores. (Brass Desk Bells at Amazon -- Affiliate Link.)
The photo at left shows the disassembled bell. The base + clapper is screwed down to the bell base, and then the hemispherical bell is threaded onto that.
Here are some photos of building track. I made my track out of 3/4" wide by 1/4" thick stock. Three pieces are glued together to make the U-shaped track. This long piece can than be cut down to the shorter pieces that are arranged to make up the different parts of the racetrack.
Keep aside some of the 3/4" wide stock, and it can be cut down to short pieces and glued in to make the end pieces for the various track segments.
I also made some notched sections of track. This can be done either with a dado blade set to 1/4" width, or by repeated cuts over a regular saw blade. The notches cause the balls to make a sort of rat-a-tat sound as they roll down.
I set the plywood back into a notch in the base. You want a pretty thick piece for the base, to give some weight to the racetrack, so that it does not easily tip over. You could cut that with a dado blade and fit the back into the slot. I did this a different way. I did not have a thick piece for the base, so I glued together two boards. But I first ripped one narrower, glued the two pieces together. Then I added the back board and a piece on the back of the base, and glued and clamped it all together.
You need to start at the bottom with laying things out. The reason for that is simple: you need to ensure that the marbles will drop nicely into the catch area.
This is an iterative process: Clamp some track in place, drop the marble through it, make sure it works, make any necessary adjustments, and then mark the location and add glue and clamp it permanently in place. Now repeat.
You could use nails from the back to fasten the track into place. However, you need to ensure that the nails do not poke through the relatively thin sides of the track!
Repeat this process all the way up the board, clamping, testing, and gluing your track pieces into place.
I made two basically identical tracks. Each track has the same elements, though not entirely arranged in the same order. As well, one set of track was made with walnut and the other with ash, to give a nice visual contrast.
Here are a bunch more photos...
BELOW: Here are a couple of sketches with a few basic dimensions. I think the idea and process is more important than precise dimensions, as I would hope that every track is going to be a bit different. As well, you can follow the links below to see a much more detailed build article and plans.
This project was published in the Winter 2008
This magazine has since ceased publication, though as of September 2015 I note that their website is still online and has my article about this project available there.
This project was also published in the 2015 edition of "Gizmos and Gadgets" from Scrollsaw woodworking & Crafts (www.scrollsawer.com). Available in October 2015, on newsstands in the USA and Canada -- and maybe elsewhere. Detailed instructions and plans are contained there.
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